Two mysteries exist on the Penguins blue line: Will Kris Letang play again this season, and who replaces him during the playoffs should he not be available?

Robert Bortuzzo has made a case to be that man.

The physical Thunder Bay, Ontario, native was used as the Penguins' No. 6 defenseman against the Jets in Winnipeg on Thursday and is receiving rave reviews from assistant coach Todd Reirden, who oversees the defensemen.

“He has really done a great job recently,” Reirden said. “He's sending a pretty loud and clear message that he wants to have that spot, to be in the lineup, if Kris isn't available.”

Bortuzzo hasn't been a healthy scratch since March 15 and, in the subsequent 11 games, is a plus-4.

The math is simple for Bortuzzo.

Defensemen Brooks Orpik and Paul Martin will see plenty of minutes as the top pairing, and the coaching staff likely will keep Matt Niskanen and Olli Maatta together.

“Our best pairings have been Brooks with Paul and Olli with Matt,” Reirden said.

Defenseman Rob Scuderi also is a lock to be in the lineup when the postseason begins April 16. Letang likely will play with him should he return, and such a scenario hasn't been ruled out. Skating almost daily, Letang looks strong on the ice. Still, whether he will return from a January stroke remains unknown.

The contenders to play with Scuderi should Letang not return are Bortuzzo, Simon Despres and Deryk Engelland.

“We're still in the process of defining how we want our pairs to look,” Reirden said.

Much could depend on the matchup. The Penguins likely will play Detroit or Columbus in the first round, although Philadelphia and Toronto remain a mathematical possibility.

While the Red Wings and Maple Leafs rely on their speed, the Flyers are bigger and play a more rugged style.